The present invention relates to exhaust gas recycling devices and a process for producing the device.
The term "aluminum" as used herein and in the appended claims includes pure aluminum and aluminum alloys.
It is generally thought that the nitrogen oxide (NO.sub.x) concentration of exhaust gases from gasoline engines can be reduced most effectively by returning a portion (5 to 20%) of the exhaust gas to the intake gas, i.e., by the EGR (exhaust gas recycling) method. When subjected to the high temperature of combustion gases, the nitrogen and oxygen in air react to form nitrogen oxides. Accordingly, the recycling of the exhaust gas lowers the temperature of combustion gas to inhibit the reaction between nitrogen and oxygen.
The device for recycling exhaust gases is interposed between an EGR valve and the intake manifold of the gasoline engine. Heretofore known as such devices are those prepared by casting.
However, the conventional exhaust gas recycling devices made of casting have the problem of consisting of many parts and being cumbersome and costly to manufacture and heavy.